How to convert an an opencv image using cvBridge??

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Here is a snippet of code I have used to do this and the full code is here. It is a package that also uses opencv to grab images and publish them. Some of the variables are:

image_transport::ImageTransport transport;
image_transport::CameraPublisher image_pub;
camera_info_manager::CameraInfoManager info_mgr;

And the code:

        // if subscribers, pub images
        if(image_pub.getNumSubscribers() >  0) {

            ros::Time time = ros::Time::now();

            // convert OpenCV image to ROS message
            cv_bridge::CvImage cvi;
            cvi.header.stamp = time;
            cvi.header.frame_id = "image";
            cvi.encoding = "bgr8";
            cvi.image = cv_image;

            // get camera parameters 
            sensor_msgs::CameraInfo info = info_mgr.getCameraInfo();
            info.header.stamp = cvi.header.stamp;
            info.header.frame_id = cvi.header.frame_id; // whatever it is called
            info.width = cv_image.cols;
            info.height = cv_image.rows;

            sensor_msgs::Image im;
            cvi.toImageMsg(im);
            image_pub.publish(im,info);
        }